北京东南郊典型地层重金属分布特征与潜在生态风险

Distribution Characteristics and Potential Ecological Hazards Assessment of Soil Heavy Metals in Typical Soil Profiles in Southeast Suburb of Beijing

选择北京东南郊地区典型污染场地,基于不同地质剖面重金属（Cu、Pb、Cr、As）的分布特征分析,运用多元统计分析和潜在风险指数方法,研究土层中重金属的分布特征与潜在生态风险评价.结果表明,研究区土层剖面重金属含量大小顺序均为：Cr〉Cu〉As〉Pb,3^6 m地层重金属的变异系数介于59.60%^159.33%,均属于高度变异.重金属Cu、Pb含量与有机质（SOM）、阳离子交换量（CEC）等具有显著正相关性,在第1和第2因子上具有较高载荷系数,表现出土层有机胶体类组分对于重金属赋存的影响.典型地层重金属的潜在风险程度：As〉Cu〉Pb〉Cr,其中As含量已达到中等潜在生态风险.

To investigate the distribution characteristics and the potential ecology risk of different types of heavy metals, soil samples were collected from various stratigraphic sections in the southeastern suburb of Beijing, where soil heavy metal （Cu, Pb, Cr, As） contents were measured and analyzed using multivariate statistical analysis and the potential ecological risk index method. The results showed that the concentrations of the four heavy metals followed the order of Cr 〉 Cu 〉 As 〉 Pb with variable coefficients ranging from 59.60% to 159.33% at 3 - 6 m stratum, which all displayed a high degree of variability. The concentrations of Cu and Pb were positively correlated with soil organic matter （SOM） , cation exchange capacity （CEC） , etc, with higher eigenvalues in Factor 1 and 2, demonstrating the impact of organic colloid on the occurrence of heavy metals. The risk level of the specific heavy metal followed the order of As 〉 Cu 〉 Pb 〉 Cr, where As already showed a medium potential ecological risk in the studied area.